| Ulan buh desert in northwest of artificial oases concentrated construction since 2009,the settle mouth county and holy priest hi-tech group invest a lot of manpower and material resources,through artificial cultivation of various tree species,soil restoration governance,artificial irrigation methods,such as the regulation of development on a large scale in the area many times,and built a large area of artificial oasis,prompting the regional development of ecological environment in good condition.It is of great significance for guiding the scientific and healthy sustainable development of the artificial oasis to study the dynamic change of vegetation,determine the main driving factors of vegetation change,and put forward the scheme of tree species selection for sand control.In this paper,remote sensing technology is used to realize dynamic vegetation monitoring,and "3S" technology is applied to analyze Landsat remote sensing images from 2009 to 2019.The dynamic changes of NDVI in the study area over the years are obtained,and the main driving factors of NDVI changes in the study area are discussed,as well as the correlation with climate factors.The Landsat images in 2009 and sentinel-2 remote sensing images in 2019 were analyzed to obtain vegetation type maps by monitoring classification,guide the background investigation of artificial vegetation,and discuss the influence of artificial oasis construction on dynamic changes of vegetation types.Three buffer zones were set up outside the artificial oasis area to explore the influence of the construction of artificial oasis on NDVI and vegetation type change in surrounding desert area.The tree species and planting model of windbreak and sand fixation matched with the desert area were discussed by analytic hierarchy process(AHP).The main results are as follows :(1)from 2009 to 2019,the overall level of NDVI in the study area was low,the overall level of NDVI in the oasis area was high and changed greatly with the change of time,and the level of NDVI in the buffer area decreased with the increase of distance.Climate factor is not the main contribution factor to the vegetation index in the study area,and the change of NDVI mainly depends on the influence of human factors.(2)It is difficult for vegetation to expand by itself in the study area.Human factors have a great influence on vegetation coverage change,and irrigation is one of the important factors influencing vegetation dynamic change.(3)The main vegetation communities in the study area were tamarix,Artemisia sphaerocephora and artemisia sphaerocephora.The dominant tree species in this area were Populus alba,Salix babylonica,Hedysarum scoparium,Haloxylon ammodendron,Elaeagnus angustifolia,Ammopiptanthus mongolica,Populus euphratica,Tamarix chinensis,Artemisia desertorum,Nitraria tangutorum.(4)Based on analytic hierarchy process and field investigation,suitable tree species were selected as follows:Ylon Ammodendron,Populus euphratica,Tamarix chinensis,Lycium Ruthenicum,Amygdalus mongolica,Hedysarum scoparium,Nitraria Tangutorum,Salix Babylonica,etc.According to the vegetation cover,a variety of planting patterns are determined in the oasisBy using remote sensing monitoring technology,it was concluded that the main driving factor of ARTIFICIAL oasis NDVI and vegetation type change was human factor.Through artificial planting sand control tree species,the positive development of NDVI could be promoted and vegetation community types could be enriched.To sum up,the sand-proof tree species suitable for planting in this region are excavated to determine the planting pattern,improve the ecological function of this region,and provide powerful countermeasures for the sustainable development of oasis. |
